This invention relates to an arrangement for controlling solar heating of the interior of parked passenger cars by means of a foil layer with a controllable light transmission capacity.
A foil with a controllable light transmission capacity of this generic type is known from the German Patent Document DE 36 43 690 C2, in which use of such foil is suggested on vehicle windows and windows of buildings, for components for the purpose of passive solar energy utilization, and as display or picture elements or for optical glass.
The air-conditioning of parked passengers cars is a problem which so far has not been solved satisfactorily. Interior heating caused by incident rays of the sun can result in temperatures of +60.degree. C. and more in a parked vehicle, so that the comfort and well being of the passengers is impaired considerably after they have entered the vehicle. Since not only the air but also the interior fittings, particularly the dashboard and the rear window shelf, are heated, the interior of the vehicle cools down only slowly even with cross-ventilation. Moreover, because of the high energy requirement, air-conditioning systems cannot be used in parked cars, and heat absorbing window glass does not satisfactorily prevent the heating of the vehicle interior.
It is an object of the present invention to provide a solar heating control arrangement of the initially mentioned type, by means of which heating of the vehicle due to solar radiation is reduced effectively during parking.
According to the invention, this object is achieved by a covering, consisting of a foil layer with a controllable light transmission capacity, a reflecting layer and a carrier material, which is applied to the parts in the vehicle interior that are particularly exposed to the radiation of the sun. Switching of the foil layer between light transmitting and light absorbing states is accomplished in a simple manner as a function of the position of the ignition lock by means of a relay, with the foil being transparent when the relay is not energized, so that radiant energy is reflected by the reflecting layer. The control of the foil is virtually without losses and thus stresses the vehicle battery only insignificantly.
The principal advantage of the invention is that the interior trim parts of the vehicle which are directly exposed to the radiation of the sun, such as the dashboard, the consoles and the rear window shelf, reflect the sunlight when the vehicle is parked in order to prevent the heating of the vehicle interior, and have a dull and dark color during the driving operation in order to avoid reflections on the windows.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.